seibon rear wing

hi all. i have a 2016 WRX STI GT version (no wing). i want a wing purely for downforce for trackdays. is the seibon "OEM" design wing any good for downforce? i know that the APR, Reverie wings etc are better, but they are also much more expensive. was thinking about the seibon carbon fibre one with a gurney flap. any thoughts?